Edit Expertise: Test Drive: HP xw4600

Our tests indicate that the HP xw4600—a fast quad-core system—is a better investment for Adobe editors than an eight-core system.

The HP xw4600 workstation, configured with the new 3.0 GHz Intel Core 2 Extreme QX6850 (quad-core) processor, hits a real sweet spot for Adobe and Sony video editing applications. For other digital content-creation tasks, performance depended upon both application and project type, but we'll get to that in a moment.

If you're looking for a general-purpose workhorse, the xw4600 should be on your short list. However, if you're looking to plug a specific gap in your workflow, you'll need to identify whether a dual-core system can provide the same performance at a lower price, or whether your programs can leverage the potential of eight cores.

The xw4600 comes with two PCI Express x16 slots and five other full-length slots, including PCIe x8, PCIe x1, and three PCI slots. HP shipped my test unit with the Nvidia Quadro FX 1700, a PCIe x16 graphics card. There are three external 5.25in. drive bays; my unit came with a 16-in-one card reader and a LightScribe-compatible SuperMulti DVD Writer.

Our test unit included 4GB of DDR2-800 RAM and a 250GB 7200rpm SATA drive running Windows XP. HP includes an eSATA port, which connects to an external SATA drive, and an internal USB slot that's perfect for those expensive application dongles. You'll have to order FireWire separately, however, because it's not included with the base system. I priced this system on the HP website, and it came to just less than $4,300.

Physically, the lockable case is very similar to previous HP models, with one latch to open the case and tool-less removal and replacement of most components, including expansion cards and disk drives. It's a very efficient design for those who have to open their cases a lot. It was also one of the quietest workstations I've ever run — making it a natural for recording narrations and other basic audio recording tasks.

Table 1. Specs of the three tested computers.
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From a testing perspective, I wanted to answer two important questions: If you currently have a Core 2 Duo-based system, do the latest versions of content-creation apps leverage the QX6850's two additional cores? Second, as long as I'm buying a new computer, does it make sense to consider a dual-processor, quad-core system?

Fortunately, I had two other relevant systems to run through the same series of benchmarks. At the low end was the Core 2 Duo-based HP Compaq 8710p notebook, which would help us see how a quad-core performed against a dual-core. At the high end was a dual-processor, quad-core HP xw8400. The two workstations ran Microsoft Windows XP, while the notebook ran Microsoft Vista.

All three systems ran at different speeds (Table 1). To normalize the results, I multiplied the number of cores times their speed, and then compared that number to the performance results with the various tested programs. If a program fully used the two additional processors in the xw4600, it should outperform the 8710p by about 2.72X. Similarly, if a program fully used the eight cores in the xw8400, it would outperform the 8710p by 4.8X, and the four-core xw4600 by 1.77X.

I looked at three classes of software: editing and authoring, 3D design, and streaming encoders.

Table 2. Rendering performance for Adobe CS3 Production Premium.
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For editing and authoring, I looked at two components of Adobe CS3 Production Premium and Sony Vegas. In my Adobe test, I produced two projects, with the first being my standard 3.5-minute HDV test project with color correction, backlight correction, speed changes, chroma key, still-image pan and zoom, logo overlay, and audio mixing. I rendered this to a Blu-ray-compatible MPEG-2 file on all three computers using the same Premiere Pro output preset. The second project involved producing a 2-minute Blu-ray Disc image from HDV source material in Adobe Encore. Table 2 shows the Adobe results.

In producing the Blu-ray-compatible MPEG-2 file, Premiere Pro proved wonderfully efficient at using four processor cores, coming close to the theoretical target of a 2.72X performance bump over the notebook. On the other hand, performance on the eight-core system was unimpressive. A look at the Performance tab of Windows Task Manager in both systems shows why.

Table 3. Rendering performance for Sony Vegas.
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When rendering on the dual- and quad-core systems, Premiere Pro was red-lined at 100 percent for the bulk of the encoding cycle. However, with the eight-core system, processor efficiency hovered around 60 percent to 70 percent.

I ran four CS3 rendering tests on all three systems (essentially the same tests using DV and HDV sources). In all four, Premiere Pro rendered at least twice as fast on the xw4600 than the 8710p — persuasive evidence that jumping from two processors to four should boost rendering performance. In three of four tests, the xw4600 was actually 20 percent faster in DV-rendering tests than the xw8400. This would seem to indicate that a quad-core system is a much better investment for Adobe editors than an eight-core system.

The Sony Vegas story, shown in Table 3, was similar — only more pronounced. In Blu-ray and MPEG-4 rendering trials, Vegas either nearly achieved or blew away the expected 2.72X speed boost, but the xw4600 system was at least 25 percent faster than the xw8400 eight-core system in both tests.

Table 4. SPECviewperf 10 performance. Results presented in seconds.
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I ran two types of 3D design tests on the xw4600: the SPECviewperf 10 benchmark to test the OpenGL graphics performance, and two rendering trials in Autodesk 3ds Max 8. I couldn't get the SPECviewperf tests to finish running on the 8710p, which is why it's not included in Table 4.

While both workstations had PCIe x16 slots, the xw8400 came with a Quadro FX 1500 card, which is a PCI Express-only card, while the FX 1700 supported the full bandwidth of the PCIe x16. Although both cards are mid-range products in the Quadro product line, the xw4600 outperformed the xw8400 by 38 percent.

SPECviewperf tests graphics performance almost exclusively, and I'd guess that if I swapped graphics cards and ran the tests again, the xw8400 would win by the same 38 percent. Clearly, to maximize OpenGL graphics throughput, get the fastest graphics card your system will support.

Table 5. Autodesk 3ds Max rendering test results.
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To test processing power, I ran two rendering trials in 3ds Max 8 (Table 5). I rendered two tutorial files from the installation disk: Shop Daylight from the mental ray folder, and Commander Lake from the Character Animation folder. I rendered both to 1920×1080i resolution, outputting in MOV using the Apple Animation codec.

In the Shop Daylight project, which incorporated complex lighting, 3ds Max proved wonderfully efficient with using multiple cores. The four-core xw4600 exceeded the theoretical maximum by rendering in 2.78X, and the xw8400 come close to its potential, rendering 4.18X faster than the notebook. In the Commander Lake character animation tutorial, 3ds Max wasn't nearly as efficient, and neither system doubled the performance of the notebook. Obviously, when it comes to rendering performance, the benefit of the additional cores will vary by project type.

Table 6. Rendering performance for streaming media encoders.
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The third leg of my testing involved three streaming media encoders (Table 6). First was On2 Flix Pro, where I rendered a 3.5-minute test file to the same Flash parameters on the three test computers. Flix Pro proved a complete dud when it came to multithreaded rendering performance. The xw4600 performed at 131 percent of the 8710p's speed, which pretty much amounts to the differential I would expect between two single-processor systems running at 2.2GHz and 3.0GHz. Similarly, the 13-percent differential between the 2.66GHz xw8400 and 3.0GHz xw4600 corresponds to the 13-percent differential between the processor speeds.

On the xw4600, Flix Pro uses only 25 percent of overall processor potential, indicating a dearth of multiple-processor efficiency. On the xw8400, overall use was 13 percent. If you're buying a workstation primarily to produce Flash videos with Flix Pro, buy the fastest single- or dual-processor system you can find, because four and eight cores are clearly a waste.

The results for Grass Valley ProCoder and Sorenson Squeeze are for a 1-minute file that is encoded to four different output types: Flash, RealMedia, Windows Media, and H.264. It's important to note that with these encoding programs, however, the results and comparative performance are almost completely dictated by the number of files in the batch and the formats produced. For example, ProCoder is glacially slow when producing Flash files, especially compared to Squeeze. The situation reverses with Windows Media, especially on the xw8400. Therefore, one test does not represent the universe of potential results.

Overall, however, both programs clearly leveraged the xw4600's four cores to some degree, and neither proved the case for an eight-core system. When buying for streaming encoding, buy speed first, then multiple cores, but don't go beyond four cores unless you're sure that your particular parameters warrant it. With the QX6850 processor, the xw4600 is the fastest quad-core system around, making it a safe choice — if not as clear as the results shown for Adobe CS3 Production Premium and Sony Vegas.

Overall, this leaves the xw4600 as a great choice for editing. The tested programs seem wonderfully optimized for its high-speed, quad-core processor. Suitability for streaming media production and 3D design and rendering is not nearly as clear-cut, and it will depend upon the program used and project type.

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